The present invention relates to a drive unit for operating a plastics injection machine.
Plastics injection machines of a type involved here include an extruder having an extruder screw for producing a plastic melt and a drive for operating the extruder screw, and an injection unit which receives the plastic melt for introduction into a cavity of a mold. A problem facing an operator of such plastics injection machines is the necessity to remove the extruder screw from the machine for cleaning purposes, when injection material needs to be changed or after the machine has cooled down. Removal of the extruder screw is conceivable in two directions. On one hand, the extruder screw may be withdrawn through the front of the extruder, i.e. in a direction away from the drive. This approach requires, however, a dismantling of the extruder and thus is very complicated and essentially impractical. As an alternative, the extruder screw may be withdrawn through the rear of the extruder, i.e. in a direction toward the drive. This approach requires, however, an undesired dismantling of the drive.
It would therefore be desirable and advantageous to provide an improved plastics injection machine and in particular to so construct a drive unit to obviate prior art shortcomings and to allow a simple removal of the extruder screw.